Process of recovering metals



Patented Nov. 7, 1922.

UNITED STATES PATENT oFF'lc ALEXANDER L. DUVAL nADRIAN, OF WASHINGTON, PENNSYLVANIA, SSIGNOBTO, B. l. DRAKENIELD & CO.II INC., 01 NEW YORK, N. Y., A CORPORATION OF NEW YORK.

rnocnss OI BECOVEBING METALS.

Application filed November 7, 1919. Serial No. 338,260.

To all whom it'mwy-com'ern."

Be it known that I, ALEXANDER L. DUVAL nAnnIAN, a citizen of the Republic of France, and a resident of 'Washin on,

5 county of Washington, and State of ennsylvania, have invented certain new and useful Improvements in Processes of Recovering Metals, of which the following is a specification.

' Heretofore in the production of the oxides or salts of chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel from their ores, disadvantages have been encountered in obtainingthe oxides or salts, free from the iron that may be present in the ores, or in. the residues, or free from other impurities, or in the se aration of one or more metallic compoun s from a group.

The object of my invention is to provide a rocess by means of which the oxides or sa ts such as chlorides, of chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel, may be readily obtained from their respective ores or from residues containing chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel, by means-that are sim le and eflicient and commercially practica le.

In order to carry out my invention, I will describe the same in the light of one embodiment, and more particularly refer by way of example, to the treatment of chromium ore, and the obtaining of chromium oxide from the ore, with the understanding,

however, that parts of this process may be applied to the treatment of zirconium, vanadium, uranium, cobalt, silver or nickel, with, however, certain modifications which will hereinafter appear. I s

In carrying out my rocess, for the purpose of obtaining chromium oxide practically free from iron or other impurities, I take the chromium ore as it comes from the mines, and grind it very finely int-o powdered form. This chromiu'm ore is usually called chromite. The object of grinding'the ore'int'o finely powdered form, isto get as large a surface as possible so that it may be readily treated as hereinafter described. This powdered chromium ore is thenmixed with sawdust and with molasses, or with a starch and water mixture, or any other suitable organic compound maybe used, adapted to serve as a bonized. Chlorine binder. The preferable proportions are about as follows, as an example:

Chromium ore in 100 parts; sawdust in 15 parts, and the binder in 5 parts.

This mass is then formed into bricks or blocks. These bricks or blocks are then placed in a furnace having a closed muflle, and heated. The heating to which the bricks or blocks are sub'ected, first carbonizes the sawdustand the inder. Thereby the particles of the chromium one are separated from each other by spaces filled with gases, and by the carbonized articles, by reason of which the bricks or locks become of a porous character, and a large surface of exposure of the chromium ore is obtained after the sawdust and binder has been caras is then injected into the furnace. The chI blocks or bricks and acts on the ore. The chlorine gas is injected through a tube from a, suitable storage tank. The muflle during the introduction of the chlorine gas, is brought to a temperature at'which the evolution of the iron chloride commences. It is advantageous to maintain the muffle temperature between approximately 450 C. and

orine gas penetrates the 1000 C., depending upon the ores to be treated. It is here to be noted that various chromium ores, even from the same mine, require variations in the treatment with respect to the temperatures. The iron of the chromium ore sublimes at about 450 (1., though some iron chloride is formed attemperatures below this. It is preferable not to go beyond 1000 C. because chromium chloride sublimes at about-1065 C. The chlorine gas combines with the iron in the chromium ore, and forms iron chloride which passes out of the furnace, flowing through a pipe line. This pipe line, may be made transparent b the use of glass or the like, or may be provided with some transparent window so that the contents flowing throu h the pipe may thereby be visible and may inspected. This iron chI'oride passes through the pipe in the form of a thick vapor of a brown color. The passing of the chlorine gas is continueduntil no further considerable iron chloride asses through the tube or exhaust pipe whic may be readily determined b inspection. In some cases, it is preferable to inject a slight amount of steam rine gas. This s'team acts to form a certain amount of chloride of iron contalning six molecules of water (FeCl 6(H,O)), which very readily volatilizes, namely at atemperature of about 280 to 285 C. The injection of the chlorine gas is continued until the brown vapor practically ceases, whereupon it is shut ofi'f It may be mentioned that when the brown vapor stops, practically all the iron of the ore has been combinedwith the chlorine s,.'and carried off in the form of iron ChlOlfldG. I This may be conducted to cooling vessels wherebyit may be condensed into a marketable article, by the utilization of temperatures below about 450 C.

The heating operation is continued for about fifteen minutes or more, to assist in driving oflr any iron chloride which may be in the muflle, and air is passed through the muflle to eliminate as much as possible an chlorine gas present in the mufile. It is pre erable to use moist air. The air also brings about the combustion of the carbon particles. The remaining content of the mufile is composed of chromium oxide with some chrome chloride, and small amounts of silica or other impurities, but practically free from iron.

After the chrome oxide has thus been obtained practically free from iron,.the chromium oxide and any chromium chloride remaining in the furnace are taken out of the furnace and the chromium oxide is freed from the chromium chloride by dissolvin out the chromium chloride in a manner wel known to the art.

For commercial purposes, it is referable to use a rotary mufiie kiln or mu e furnace.

In the use of a rotary furnace, no molding of the ore is necessary. This is due to the agitation to which the ground ore is subjected by the rotation of the furnace and the consequent production of new surfaces of contact of the particles of the ore with the gas in the muffle. In the use of a rotary furnace, the ore in finely powdered form is mixed with carbon and then heated and subjected to the action of the chlorine gas for the elimination of the iron from the ore. It is not always necessary to use the carbon. It has been found that with the use of carbon, lower temperatures ma be utilized as the presence of carbon-facilities and makes more rapid the action of the gas. The treatment of the contents of the muflie is carried-out as above described. The remaining chromiuin oxide with chromium chloride such as remains in the furnace, is treated as above described, namely by dissolving out the chromium chloride in a manner well known to the art. Whatever silica remains here, as. also in the furnace before mentioned, may be removed by processes well 'known in the art, as for example, by hydrofluoric acid.

The process as above described, is based upon the regulation of the temperatures during the passage of-the chlorine gas through the furnace and its coming into contact with the ore, it being important to so reguture; chromium chloride is formed and sublimes, and which carries out the process until all of the materials in the furnace are volatilized and sublimed in the form of chlorides.

In this process, temperatures are utilized A from 450 C. upwards.

In the accompanying drawing I have disclosed a typical apparatus by means of which the present process may be successfully prac-. ticed. In this drawing 5 designates the rotary mufiie kiln or furnace having an outer Wall or shell 6 of refractory material. To

one end of the rotary kiln a chlorine gas storage tank 7 is connected through the mediumof the pipe 8, whichis coupled to a pipe 9 for supplying air under pressure, and to a steam supply pipe 10. A suitable as tight fitting or connection is provided etween the 'gas supply pipe and the end of the rotary kiln. A series of condensers 12. areconnected in series to each other, each con-' denser bein arranged in conjunction with a heating c amber 13. The first condenser in the series is connected by a gas tight fitting 14 to the other end of the rotary kiln, while the last condenser in the series is connected by a pipe 15 with a pump 16, which creates a partial vacuum in the several condensers and draws the chlorine'gas entering the condensers from the furnace through the said pipe 15, and returns the same to the storage tank 7 through the pipe connection 17 between said tank and the pump 16. It will be understood that the drawing is simply illustrative of one possible construction of apparatus which may beemployed in the practice of my improved process on a commercial basis.

It will be readily appreciated that various other alternative constructions might be employed. Thus, as hereinafter noted, instead of providing the single condensers 12, a plu rality of groups of condenser units may be utilized, and such .groups of units connected in series with each other whereby a succession of condensations will occur in each co n I time that the ore is sub'ected to the temperatures ranging from t e initial temperatureof 450 C. and'then throu h the various temperatures up to 1065 and above 1065 C. the vapors or sublimates are conducted from the furnace into condensers. These condensers are arranged in series, that is, the first condenser is in communication with the furnace and thereafter each followlast ing condenser communicates with. the one preceding. These condensers are maintained at different temperatures. The first condenser, or. in case more than one .is desired to be used, then the first condenser or the first group is maintained at one constant temperature, and this temperature is higher than any of the other temperatures in any of the other condensers. The temperature of the first condenseror group of condensers is selected to bring about the deposit of chr'omium chloride. If chromium chloride is maintained at a temperature less than 1065 C., it will deposit. For this reason the first condenser or the first group of condensers which has for its object to bring about the deposit of the chromium chloride, are maintained at a temperature between 460 to 500 C. All substances which maintain their subliming at temperatiires below 500 C. will flow from the first group of condensers to the next or number two group This number two group of condensers is maintainedat a temperature below 450 C. but above 220 C. It is within this range of temperatures that iron chloride deposits inthe form of FeCl,. The other substances which keep on subliming,.pass off or continue into the number three group of condensers. This third group'of condensers is maintained at a tern erature below 57 C. and above 40 C. is range of temperatures brin s about the deposit of various silicon ch orides, as per example, SiC'l below 145 (3., SiCl below 57 (1., and Si C1, below 210. C. Certain substances, as for instance FeCl 6(H. ,O) are carried off from these condensers into a next group, and this roup is kept at tern eratures below 5, whereupon the Fe 1 6(H O) deposits.

I have spoken ofgroups of condensers for each ste but it is clear that in some cases, one con enser may take the place of a group.

' The advantage, however, of more than one condenser for each step is that in the first condenser of a step whereln it is desired to deposit chromium chloride, perhaps not the entire quantity of chromium chloride will deposit, and part of the chromium chloride will be caroup, for instance at the ried ofi' with the remaining chlorides, and deposited in a subsequent unit of the same group. Similarl in the second step where and deposit, all the various chlorides which have passed out of the furnace will be indi vidually isolated. i

The chromium chloride deposited in the first condenser or a group of condensers, is thentreated in a manner well known to the art to secure chromium or its compounds, as for instance chromium oxide. Similarly, the

other chlorides may be utilized. Such portions of chlorine gas as comes from the mufile and ass through the condensers, may be collecte and recovered.

In carrying out the process, it must be remembered that ores from the same mine are di-fi'erent in their characteristics andthat it has been found desirable to select portions of the ore desired to be treated and subject them to a preliminary test to ascertain their characteristics. When this preliminary test has been completed and the characteristics of the ore have been ascertained, then one of the above two methods of treatment may be employed as abovedescribed. Some ores will be better treated with a selective volatilization, others with a complete volatilizaores whic may contain silica, iron and titanium, the zirconium,-titaninm, silicon and lron can be simllarly separated. In case of cobalt ores, which,in addition to cobalt, 120

usually contain nickel, silver, iron, arsenic, antimony and silicon, these may be all selec tively condensed, or the cobalt ore may be first roasted to remove arsenic and antimony, andthen the cobalt, nickel, silver, iron and silicon, selectively condensed. I have spoken of ores, but it is clear that residues may be similarly treated. i

In the case of a cobalt ore or a residue containing cobalt, it is necessary in carrying out the above described methods, to rememberand guided thereby, that cobaltchloride sublimes at tem eratures about 700"v C. imes at temperatures C. and nickel chloride sublimes at te'm eraturesabout 600 to 700 Arsenic an antimony is usually generatedby roasting Silver chloride jsub ;,at-temperatures below about 130C. The dif- 750 c. .TheQi-ron chloride and" F801, i .6( H,'O) ,distilli'as '25 .zlead chloride sumblimes at about 861 to "acid, I I

In the'case ofzirconium 136 C. The siliconchlorides andfliron I chlorides asheretofore-and the zirconiumchloride at 4009C.

'ferent antimony chlorides distill at various t ut 0 .0-,-@ low about225" 0. The iron chloride as here .tofore, sublim s, at about 4503C. and the v 'FeCl, '6 (11,0). distijlls at below about"'37 (l. i The silica chlorides distill at temperatureslas =SiCl, below' about '145*C.,' 1 "f temperatures 've, a

follows:

SiCl', below about 57 0.;

' 51,01, below about .210 "c. In the case of vanadium ore or residues, theseveral vanadium chlorides,

C [Uranium chloride distills below: about 'he retofore stated. Silica. chlorides distilled as heretofore stated. The

954 C. and the barium chloride is leftas an ores or residues,

titanium chloride: distillsat below about Among the ore residues that I havetreated is speiss. I'have also treated metal alloys forhe separation-of 'the metals composing the same. I believe my methods are also applicableto the treatmentof slags and mattes.

I have described the above as embodimentsof my invention but it is clear that changes may be made therein without departing from the spirit and scope of the invention as definedin the appended claims. 7

I claim:

1. The process of obtaining chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel in the form of oxides or chlorides or other chlorine compounds from their respective ores, or from residues containing chromium, zirconium, vanadium, uranium,

cobalt, silver, or nickel, which consists in subjecting an ore or residue to a heat treatment in the presence of. chlorine gas, for combine chloride rom the ore or residue.

in the iron of the ore or residue with the ch orine as, and then removing the iron 2. The process of obtaining chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel in the form of oxides or chlorides or other chlorine compounds from their re spective ores, or from residues containing chromium, zirconium, vanadium, uranium,

cobalt, silver or nickel, which consists in subjecting an ore or residue to a heat treatment in the presence of moist chlorine gas, for

and arsenic chloride distills distill at be lot; at above about 126.5 C., and below 154 combining the ironof the ore or residue with the chlorine gas, and then, removing the iron c hloride :fromthe ore orre'sidue.

3. The zirconium vanadium, uranium, cobalt, silver, or nickel n theform ofoxides or chlorides spective ores, or from residues containing chromium, zirconium," vanadium, uranium, cobalt,flsilver, f.or"nickel, which consists in subjecting oreor residue and carbon mixed w therewith to heat treatment in. the presence-off chlorine. 7 for combining the iron of the'ore orresidue with thechlorine rom theore or residue. 1 .4. The proces-of obtaining chrom um,

and, henremoving the iron chloride process of obtaining chromium, I

or other chlorine compounds from their re zirconium, vanadium, uranium, cobalt, silver, or nickel in the form of oxides or chl0 .rides or other chlorine compounds from their respective-ores, or from residues containing chromium, zirconium, vanadium, 'uranium, cobalt, silver, or nickel, which consists in heatingan ore or residue in the presence of carbon, then subjectingthe ore; or. residue and carbon to further heat 'treatmentat a relatively higher temperature and to the simultaneous action of chlorine gas, to thereby'form agchloride and then removing the lchloride. rx v *5.-The}step in th'e art, whichconsists in removing the iron from chromium, zirconium vanadium, uranium, cobalt, silver, or

'n'ickel ores or residues, containing chromium,zirconium, vanadium, uranium, .cobalt, silver, or nickel, by combining the. iron of -the'ore' or residue with chlorlne" gas under theaction oi heat to form iron chlorides.

6. The step in the art which consists in converting the constituents of chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel ores or residues containing chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel, to chlorides, by combining the metals of the ore or residue with chlorine gas under the action of heat.

7. The rocess' of recovering chromium and ironrom ores or residues containing the same and separating them from each other, comprisin finely grinding the ore or residue 'to obtaln a large reaction-surface, mixing the same with an easily carbonizable fillerand binder, briquetting the mixture, heating the same to 'carbonize the filler and binder to produce a highly porous texture,

whereby the subsequent action of chlorine as on the metal-contentfof the mixture is acilitated, subjecting the latter to the action of chlorine cient 'to distill t e iron chlorides but not chromium chloride,

gas at a temperature sufliheating the same the same and separating them from each other, comprising finely grinding the ore or residue to obtain a large reaction-surface,

mixing the same with sawdust and a binder,

briquetting' the mixture, heating the same to carbonize the filler and binder to produce a highly porous texture, whereby the subsequent action of chlorine gason the metalcontent of the mixture is facilitated, subjecting the latter to the action of chlorine as at a temperature sufiicient to distill the iron chlorides but not chromium chloride, condensing the iron chlorides and treating the remaining reaction-mass to recover the chromium contents.

9. The process of recovering chromium and iron from ores or residues containing the same and separating them from each other, comprising finely grinding the ore or residue to obtain a large reaction-surface, mixing the same with an easily carbonizable filler and binder, briquetting the mixture, to carbonize the filler and binder to produce ahighly porous texture,

whereby t e subsequent action of chlorine gas on the metal-content of the mixture is facilitated, subjecting the'latter in the presence of steam to the action of'chlorine gas at a temperature suflicient to distill the iron chlorides but not chromium chloride, condensing the iron chlorides and treating the remaining reaction-mass to recover the chromium contents.

10. The process of obtaining chromium, zirconium, vanadium, uranium, cobalt, silver, or nickel in the form of oxides or chlorides or other chlorine compoundsfrom their respective ores, or from residues containing chromium, zirconium, vanadium, uranium, cobalt, silver,- or nickel, which consists in subjecting an ore or residue to a heat treatment in the presence .of chlorine gas, for combining the iron of the ore or residue with the chlorine gas, and then 1 removing the iron chloride from the ore or residue,-so as to leave the other metallic constituents as oxides or salts.

In testimony that I claim the foregoing as my invention, I have signed my name hereunder. a

ALEXANDER L. DUV AL dADRlAN. 

